This invention relates to a safety post assembly for assisting entry to or exit from the upper portion of a structure and, in particular, to a safety extension post removably secured to the upper end of a ladder in a manhole to provide grasping means during entry to or exit from the upper portion of the ladder.
There are a number of prior art devices which are directed to providing for increased safety in exiting from or entering to the upper portion of a ladder or other structure, especially fixed ladders having a hatchway at their upper end. In general, some of these devices provide a rail or auxiliary support so that the ladder user can grasp the rail and thus improve his or her balance and stability while using the ladder. Some prior art devices also essentially extend the useful reach of the ladder by providing a support means at the upper extremes of the ladder.
In U.S. Pat. No. 4,546,855, the disclosure of which is hereby incorporated by reference, there is disclosed and claimed a safety extension adapted to be mounted by various adjustable means to the upper rungs of a ladder, particularly the ladder inside of a manhole. The safety extension comprises a rod which is adjustable in a sleeve between extended and retracted positions. The rod is nonremovably secured in the sleeve which includes adjustable mounting means to accommodate ladders of different rung spacing and rung diameter. A coil spring counterbalance facilitates upward and downward movement of the rod.
While the extension rod of U.S. Pat. No. 4,546,855 provided a considerable improvement over the prior art, especially in connection with manhole ladders, it requires a somewhat expensive and complex assembly which must be completely supplied for each manhole ladder. In addition, the counterbalance assembly must be provided to accommodate the full weight of the post. Also, the safety extension provides no additional step for entry to or exit from the manhole ladder.
Bearing in mind these and other problems in the prior art, it is therefore an object of the present invention to provide a portable safety post extension assembly for assisting entry to or exit from the upper portion of a structure.
It is another object of the present invention to provide an effective safety post assembly which is less costly than those heretofore known.
It is a further object of the present invention to provide a safety post assembly which is of simple design, yet which facilitates use with various types of structures.
It is yet another object of the present invention to provide a safety post assembly which provides a foothold for facilitating entry to or exit from the upper portion of a structure.
It is a further object of the present invention to provide an improved safety post assembly which is easy to ship and transport for use with more than one strucuture.